Automatic fire alarm



. July 2, 1929. F. F. RANDOLPH AUTOMATIC FIRE ALARM Filed April 6, 1927gmnmto'o F'Z'PandoZ uh:

Patented July A 2 1929.

' 1,719,672. 'JUNITTEDYSTATES. PATENT. OFFICE.

FIt EID r. RANDOLPH, or FISKDALE, MASSACHUSETTS.

AUTOMATIC FIRE ALARM.

Application filed April 6,

This invention relates to alarm mechanism and provides for the automaticgiving of warning in the event of fire or the abnormal rise oftemperature from any cause.

The invention contemplates an electric circuit and a signaling devicetherein, such as an electric bell, which, when the circuit is closed,operates to give warning of impending danger from fire.

The invention consists of a thermally controlled electric switch,included in the alarm circuit to automatically close it when apredetermined rise in temperature has been reached.

Vi/hile the drawings illustrate a preferred embodiment of the invention,it is to be understood that in adapting the means to meet specific needsand requirements, the design may be varied and such other changes in theminor details of construction may be resorted to within the scope of theinvention as claimed without departing from the spirit thereof.

For a full understanding of the invention and the merits thereof,reference is to be had to the following description and the drawingshereto attached, in which,-

Figure 1 is a diagrammatic view, illustrative of the invention.

Figure 2 is an elevational View of the circuit closing switch.

Figure 3 is a horizontal sectional view on the line 3- -3 of Figure 2.

Figure 4: is a perspective view of the fuse.

Corresponding and like parts are referred to in the followingdescription and designated in the several views of the drawings by likereference characters.

Referring to Figure 1 the letter A designates the alarm circuit, B aplurality of alarm devices, such as electric bells included in thecircuit, and C switches or circuit closing clevices, which are automaticin operation for completing the circuit under abnormal conditions andeffecting the sounding of an alarm. It is to be understood that theswitch or circuit closing device is located at the place to besafeguarded, and the alarm devices may be arranged at any determinatepoint for attracting attention when the alarm circuit is closed.Obviously, the alarm devices may be of the visual or audible type asrequired.

The circuit closing device C includes a box 1 for receiving andsupporting the coacting parts. This box is adapted to be located at anydeterminate point, and is fixed to a Wall 1927. Serial No. 181,504.

or other suitable support. A fixed contact 2 is attached to a wall ofthe box, such as the back thereof, and comprises spaced jaws 3 adaptedto receive the element 4 of the movable contact. The jaws 3 areresilient and frictionally engage the element 4, thereby assuring aclosing of the circuit when the movable contact 41 is released. Abracket 5 attached to the back of the box 1 is formed with spaced ears6, between which an arm 7 is pivoted, and which carries the movablecontact 4. An arm 8 projects from the arm 7, and extends through avertically disposed slot 9 formed in a wall of the box. The projectingend of the arm 8 is provided with a weight 10. Brackets 11 are attachedto the outer side of the box 1 adjacent to and upon opposite sides ofthe slot 9, and their horizontal portions receive clamp screws 12 whichserve to secure the fuse to the brackets.

The fuse consists of end clips 13 and a connecting wire 14 of fusiblemetal of a nature to melt at a relatively low temperature. When the fuseis in position the clips 13 rest upon the horizontal portions of thebrackets 11, and are secured thereto by means of the clamp screws 12.The fusible element or wire 14 extends across the space formed betweenthe brackets 11 and engages under the arm 8, and supports the same, asindicated most clearly in Figure 2. When the arm 8 is thus supported themovable contact element 4 is held away from the fixed contact 2, but inthe event of the element 14: fusing by an abnormal rise in' thetemperature the weighted end of the arm 8, being no longer supported,gravitates, with the result that the contact 4 engages the contact 2 andcloses the alarm circuit and gives warning of impending danger.

Lead wires 15 from thealarm circuit, are con nected to plates 16 appliedto the back of the boxl and these plates in turn are electricallyconnected to the parts 2 and 5 by means of bolts, or other suitablefastening means, thereby establishing an electric connection between thelead wires and the contact elements. The alarm circuit may contain. anynumber of alarm devices and circuit closers according to the capacityand extent of the system.

Having thus described the invention, I claimf An electric alarm circuitcloser comprising a box provided in a side wall with a vertical slot, atfixed contact within the box including resilient jaws, an arm pivotedwithin the box adapted to besecured to the brackets and normally supportthe Weighted armaind hold the pivoted arm elevated With the contactcarried 1 thereby away from the fixed contact.

In testimony whereof I aflix my signature.

FRED F. RANDOLPH. [14.8.]

